JP2000209886A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which can realize highest-efficiency operation of an IPM motor for which optimum conducting phase, in which the power supply current becomes the smallest, dynamically changes from moment to moment depending upon the rotating condition of the motor, such as number of revolutions, torque, etc., by aggressively searching the optimum conducting phase. SOLUTION: A conducting phase setting means 7 sets a conducting phase value at every specific, so that the efficiency of an IPM motor 1 is highest. At setting of the conducting phase value, the means 7 compares the preceding current value and set conducting phase value with the present current value and set conducting phase value and sets the new conducting phase value, based on the compared results. A conduction distributing means 8 decides the conducting timing of the motor 1, based on the thus set conducting phase value and the phase detected by means of a rotor phase detecting means 5, and the motor 1 is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reluctance torque generated by an inductance change of an armature winding and an armature current used for a compressor such as an air conditioner and a magnetic flux of a permanent magnet. Also, the present invention relates to a motor control device using a brushless motor of a type that is used in combination with a framing torque generated with an armature current.

[0002]

2. Description of the Related Art A brushless type of brushless type utilizing a combination of a reluctance torque generated by an inductance change of an armature winding and an armature current and a fleming torque generated by a magnetic flux of a permanent magnet and an armature current. As the motor, a motor having an embedded magnet structure in which permanent magnets are embedded inside the rotor (hereinafter referred to as IPM (Interior PermanentM)
agnet) is commonly used.
Regarding the principle of torque generation in this IPM motor,
For example, it is described in detail in the document "Rotating machine using reluctance torque (IEEJ Transactions on Electronics, Vol. 114, No. 9, 1994)". In this document, the torque generated by the magnetic flux of the permanent magnet and the armature current is called active torque, but in this specification, this is called fleming torque.

FIG. 13 is a graph showing an example of the relationship between the timing at which a current flows through the coil winding of the armature, that is, the conduction phase, various torque values, and the terminal voltage in the IPM motor. As shown in FIG. 13, the framing torque Tm becomes maximum when the leading energization phase β is 0 °, and its waveform is represented by sinβ having a peak value at the phase of 0 °. The reluctance torque Tr becomes maximum when the leading energization phase β is 45 °, and its waveform is represented by sin2β having a peak value at the phase of 45 °. Further, as shown in FIG. 13, the terminal voltage Va decreases as the advance energization phase β increases, and the terminal voltage Va is in a state of a so-called field weakening operation. Further, the total torque T is an added value of Tm and Tr, so that a larger torque can be obtained as compared with a normal motor using only the framing torque.

When the total torque T is expressed by the following equation, the following equation is obtained. T = P (φa × Ia × cosβ) tens P (1/2 × (Lq
−Ld) × Ia ＾ 2 × sin2β) In the above equation, φa represents the armature interlinkage flux by the permanent magnet, Ia represents the armature current, and Lq and Ld represent the q-axis d-axis inductance of the armature winding. In the same equation, the first term represents the fleming torque Tm, and the second term represents the reluctance torque Tr.

In such an IPM motor, when a rotation condition such as a rotation speed or a torque changes, a speed control works so as to follow the change, and an armature current changes. As is clear from the above equation, the changes in the fleming torque Tm and the reluctance torque Tr according to the increase and decrease in the armature current are not the same. Therefore, the total torque T
Is maximum, fluctuates depending on the rotation condition. In other words, the energization phase β that provides the highest efficiency changes every moment depending on the rotation condition.

[0006] Further, in the fluctuation of the total torque T, there is a range of the energization phase in which the torque value becomes extremely low as in a minus torque region in FIG. Such a negative torque region changes according to the ratio of the reluctance torque Tr and the fleming torque Tm.

Therefore, depending on the energization phase, the motor may suddenly stop (hereinafter, this is referred to as step-out) or the motor efficiency may be extremely deteriorated. For example, in the case of an IPM motor having the characteristics shown in FIG. 13, when the energization phase is made to be slightly delayed, the above-mentioned step-out and deterioration of the motor efficiency occur. Further, even if the energization phase is advanced too much, step-out or deterioration of the motor efficiency similarly occurs. The energization phase at which such loss of synchronism or extreme deterioration of motor efficiency occurs also changes from moment to moment depending on the rotation conditions.

Here, the fluctuation of the rotation condition will be considered. At present, IPM motors are often incorporated in compressors for compressors such as air conditioners. As described above, when the above-described IPM motor is used in the compressor, the fluctuation of the load torque which is one of the rotation conditions of the IPM motor has a waveform as shown in FIG. FIG. 10 shows the fluctuation of the load torque generated by each compression cycle with respect to the motor rotation angle θ in the rolling piston type and scroll type compressors. in this way,
The load torque, that is, the rotation condition varies depending on the compression cycle.

Also, in the IPM motor itself, torque fluctuations occur in one rotation of the motor due to factors such as rotor magnetization accuracy, stator coil accuracy, bearing accuracy, and the like. Torque fluctuation occurring in a cycle of the least common multiple of the number of coils, that is, so-called torque ripple occurs. The rotation condition also fluctuates due to such a torque fluctuation.

On the other hand, the rotation speed is basically kept constant because the speed is controlled by a control device, but the target rotation speed is changed from time to time by a main system such as an air conditioner. Has been given. That is, the motor rotation is controlled according to the target rotation speed.
As described above, the rotation condition varies even when the rotation speed is viewed.

When driving and controlling the motor, means for detecting a reference coil phase, that is, a rotation position detection sensor is required. In this regard, in the case where the motor is mounted in the compressor as described above, or when it is desired to minimize the cost, in order to eliminate the problem of the configuration in the compressor or the problem of cost increase, the rotor phase without sensor is used. Has been adopted. Several methods for detecting the rotor phase without using the sensor are disclosed in, for example, the document "Sensorless technology for brushless motor (mechanical design, Vol. 34, No. 17, December 1990 separate volume)". . As such a method, for example, a method of filtering a back electromotive voltage waveform generated in each coil and detecting this as phase information is generally performed.

At present, as a control method for increasing the efficiency of an IPM motor, a method called a table reference method is generally known. This table reference method refers to storing a rotational condition-efficiency characteristic result obtained in advance in an experiment or the like in a ROM in a control circuit, and retrieving a corresponding energizing phase setting value using rotational conditions such as rotational speed and torque as parameters. Set the energizing phase by
That is the method.

Next, a motor drive circuit disclosed in Japanese Patent Application Laid-Open No. 4-140093 will be described as a conventional technique for detecting a current, changing the conduction phase thereby, and performing a drive to minimize the current. I do.

This motor drive circuit is used in an ordinary brushless motor using only the framing torque to determine the energization timing based on a coil phase detection signal output from a rotational position detection sensor such as a Hall element, and the actual motor coil phase. The purpose of this method is to correct the deviation and make the two phases coincide, and as a result, the motor efficiency is improved. This is because the position where the coil phase detection signal, which is the output of the rotational position detection sensor, and the actual coil position coincide with each other, is the position at which the motor current eventually becomes minimum.
That is, by detecting the motor current and performing control to advance or delay the phase of the coil phase detection signal so that the phase is minimized, the phase at which the coil phase detection signal matches the actual coil position (optimum Shift time). This process is performed only once after the detection of the low-speed rotation immediately after the start of the motor operation, and thereafter the operation is performed according to the determined optimum shift time.

[0015]

In the conventional efficiency control of the IPM motor using both the framing torque and the reluctance torque, the energization phase is uniquely set in an open loop as in the above-mentioned table reference method. ing. In other words, since it is not to actually detect and control the efficiency or information equivalent to the efficiency, it cannot be said that accurate efficiency control is performed.

In the above-described configuration in which the energization phase is changed, it takes a certain amount of time to converge to an optimal energization phase.
Efficiency throughout the operation will be reduced.

More specifically, when the energization phase is changed, depending on the performance of the speed control circuit, as shown in FIG. 12, the generated torque and the rotation speed change instantaneously greatly, and converge to the target value. It takes a certain time Tcnt to complete. During this Tcnt, there is a problem that the rotation conditions are different from those before the change of the energization phase, and accurate current comparison cannot be performed.

The motor drive circuit disclosed in Japanese Patent Application Laid-Open No. 4-140093 corrects a deviation of a coil phase detection signal which is an output of a rotation position detection sensor. It is configured to ask for time. In other words, this motor drive circuit actively searches for the optimal energizing phase for an IPM motor in which the optimal energizing phase dynamically changes with time according to the rotation conditions, and performs accurate efficiency control. No action can be taken. Also, in the sensorless phase detection method with low detection accuracy, the optimum shift time differs for each detection timing. Further, as described above,
Setting the optimum shift time only at the initial stage cannot cope with the fluctuation of the optimum shift time.

In the above-mentioned motor drive circuit,
At the initial stage of the motor rotation, the motor is operated in accordance with the coil phase detection signal output from the rotation position detection sensor.
Such an operation cannot be applied to the M motor.

Further, as described above, in the IPM motor, there is a periodic variation in the load torque. For example, by detecting the variation in the power supply current, the motor which does not perform the control corresponding to the variation is detected. In a drive circuit, accurate and highly accurate control is difficult.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to dynamically and instantaneously change the optimum energizing phase such that the power supply current is minimized according to the rotational conditions such as the number of revolutions and torque. For changing IPM motors,
It is an object of the present invention to provide a motor control device that successively and actively searches for an optimal energizing phase to realize the highest efficiency operation.

[0022]

According to a first aspect of the present invention, there is provided a motor control device comprising: a reluctance torque generated by an inductance change of an armature winding and an armature current; A motor control device that drives a motor that uses the magnetic flux of the motor and a framing torque generated in association with an armature current, a rotor phase detection unit that detects a rotation phase of a rotor in the motor, and a power supply current in a drive power supply. Power supply current detecting means for detecting the current value of the power supply, energizing phase setting means for setting the energizing phase setting value at predetermined time intervals, the rotational phase detected by the rotor phase detecting means, and the energizing phase setting means. The energizing timing to the motor coil in the motor is determined from the energizing phase set value, Power distribution means for distributing the power signal, wherein the power phase setting means compares the current value read last time and the current phase setting value at that time, and the current value read this time and the current phase setting value at that time, respectively. A comparison is made, and based on the comparison result, the energization phase set value is increased or decreased by a predetermined energization phase change amount, and a new energization phase set value is set.

According to the above configuration, the energization phase setting means sets the energization phase set value at predetermined time intervals. In this setting, the current value read last time, the energization phase set value at that time, and the current read phase value are set. The current value and the energization phase set value at that time are compared, and the energization phase set value is increased or decreased by a predetermined energization phase change amount based on the comparison result, and a new energization phase set value is set. Is fluctuated, it is possible to successively search for and set an optimal energization phase. Therefore, the motor can always be driven with the optimal energization phase that minimizes the power supply current, so that the motor can be operated with extremely high efficiency.

According to a second aspect of the present invention, in the motor control device according to the first aspect, the energization phase setting means sets the energization phase set value according to the rotation condition when the rotation condition is changed. It is characterized in that it is set to the initial value of the energization phase setting.

According to the above configuration, when the rotation condition is changed, the energization phase setting value is set to the initial value of the energization phase setting which is set according to the rotation condition. Also in this case, the energization phase setting value is set to an energization phase suitable to some extent under the rotation conditions. Therefore, even if the rotation condition is significantly changed, it is possible to prevent the motor from stepping out or extremely lowering the efficiency, and it is possible to enhance the reliability of the high-efficiency operation of the motor.

According to a third aspect of the present invention, in the motor control device according to the first aspect, the energizing phase setting means sets the energizing phase set value within a range of a limiter value set in accordance with a rotation condition. It is characterized by.

According to the above configuration, the energization phase set value is
Since the value is set within the range of the limiter value set in accordance with the rotation condition, for example, even when the rotation condition is largely changed, in the process of searching for the optimal energization phase, the motor loses synchronism and the efficiency is extremely deteriorated. It is possible to prevent the energization phase setting value from being set to such an energization phase. Therefore, the reliability of the high-efficiency operation of the motor can be improved.

According to a fourth aspect of the present invention, in the motor control device according to any one of the first to third aspects, the energizing phase setting means determines a ratio of a change amount of the power supply current to a change amount of the energizing phase. , The amount of change in the energization phase is determined.

According to the above configuration, the energized phase change amount, which is a unit amount for increasing or decreasing the energized phase set value, is determined based on the ratio of the power supply current change to the energized phase change amount. The value can be set at a high speed to the optimum energizing phase that fluctuates according to the rotation condition, and the phase fluctuation after the energizing phase set value converges to the optimal energizing phase can be suppressed to be small. Therefore, high-speed and high-accuracy energization phase control can be performed, so that the motor can be operated with higher efficiency.

According to a fifth aspect of the present invention, in the motor control device according to any one of the first to third aspects, the predetermined time is set so as to be synchronized with a torque fluctuation of the motor. .

According to the above configuration, the predetermined time, which is the timing at which the energization phase setting means sets the energization phase set value, is set so as to be synchronized with the torque fluctuation of the motor. It is possible to do it accurately. Therefore, the search for the optimal energization phase can be performed more accurately, and the operation of the motor can be performed with higher efficiency.

According to a sixth aspect of the present invention, in the motor control device according to any one of the first to third aspects, when the rotation speed of the motor fluctuates when the energization phase is changed,
It is characterized in that the predetermined time is set to be equal to or longer than the control convergence time until the fluctuation of the rotation speed of the motor stops.

According to the above configuration, when the rotation speed of the motor fluctuates when the energization phase is changed, the predetermined time which is the timing at which the energization phase setting means sets the energization phase set value is equal to the control convergence time. Since the setting is made as described above, it is possible to prevent the fluctuation of the rotation speed of the motor from adversely affecting the search for the optimum energization phase. Therefore, the search for the optimal energization phase can be performed more accurately, and the operation of the motor can be performed with higher efficiency.

According to a seventh aspect of the present invention, in the motor control device according to the first aspect, the energizing phase setting means determines a comparison result between the current value read this time and the current value read last time at predetermined time intervals. In addition to storing the value as the value comparison result, the comparison result between the current energization phase setting value and the previous energization phase setting value is stored as the energization phase comparison result, and the current value comparison result and the energization phase comparison result are exclusive. It is characterized in that the addition or subtraction sign of the energization phase change amount is determined by performing a logical sum operation, and a new energization phase set value is set.

According to the above configuration, an exclusive OR operation is performed on the current value comparison result and the conduction phase comparison result to determine the sign of addition or subtraction of the conduction phase change amount, and the new conduction phase setting value is set. Since the setting is made, it is possible to search for the optimal energization phase without performing complicated processing. That is, the highest efficiency operation of the motor can be realized simply and efficiently.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing a schematic configuration of a motor control device according to this embodiment. As shown in FIG. 1, the motor control device includes an IPM motor 1, an AC power supply 2, an A / D converter 3, an inverter circuit 4, a rotor phase detection unit 5, a power supply current detection unit 6, a conduction phase setting unit 7, and The power distribution unit 8 is provided.

The IPM motor 1 uses reluctance torque generated by the change in the inductance of the armature winding and the armature current together with the flux of the permanent magnet and the framing torque generated by the armature current. It consists of different types of brushless motors. FIG. 2 is a sectional view showing the internal configuration of the rotor in the IPM motor 1. As shown in FIG. 2, the IPM motor 1 is a motor having an embedded magnet structure in which four permanent magnets 9 are embedded in an iron core 10 constituting a rotor. The air gaps 11 are formed in the rotor so as to penetrate the permanent magnets 9 from both ends toward the outside of the rotor.

The AC power supply 2 supplies power to the IPM motor 1. For example, when used in a general home, a 100V AC power supply is used.

The A / D converter 3 converts the alternating current from the alternating current power source 2 into direct current and supplies the direct current power to the next inverter circuit 4.

The inverter circuit 4 includes an A / D converter 3
An AC power supply having an arbitrary frequency is generated from the DC power supply supplied from the IPM, and an AC power supply having a desired frequency is supplied to the IPM motor 1. This makes it possible to smoothly change the rotation speed of the IPM motor 1 to an arbitrary value.

The rotor phase detecting means 5 includes the IPM motor 1
Is to detect the rotational phase of the rotor from the back electromotive voltage in the non-energized section of the three-phase coil terminals U, V, W.

Incidentally, the rotor phase detecting means 5 is not limited to the above-described configuration, but may be, for example, a configuration obtained from a motor neutral point potential or a configuration obtained by calculating from a motor current. It is. Especially 180
In the case of energization, there is no non-energization section and no back electromotive voltage is generated, so the configuration of the present embodiment cannot be used, and another configuration as described above is used. 180 °
The energization is an energization method in which no energization period exists when energization of one coil terminal is viewed in time. Originally, the energization cycle is 360 °, but in the case of a three-phase motor, the phenomenon can be understood by focusing on the 180 ° period.
180 ° is the reference.

The rotor phase detecting means 5 in the so-called forced excitation drive system for forcibly switching the energization to each coil terminal for driving is to detect a switching signal for forcibly changing the energization. do it.

Further, the rotor phase detecting means 5
It is also possible to adopt a configuration in which the PM motor 1 is provided with rotation detection means such as an encoder. In the case of such a configuration, a problem of cost increase and a problem of processing of a space required for mounting the sensor remain, but the rotation phase of the IPM motor 1 can be accurately detected. In the case of a brushless motor that uses reluctance torque, the maximum torque is generated at different energization phases depending on the rotation conditions as in the above equation, so not only means for detecting the rotation phase of the rotor, but also the optimum energization phase described later. Control is required.

A speed control circuit (not shown) is connected to the rotor phase detecting means 5. The speed control circuit detects a difference between a rotation speed target obtained from a system control device (not shown) and rotation information obtained from the rotor phase detecting means 5, and outputs this as a speed control signal. Based on this speed control signal, the IPM
The rotation speed of the motor 1 is brought closer to the target value.

The power supply current detecting means 6 includes a current transformer C. T. The waveform is shaped by receiving the output of (1), and the current value is detected.

As described above, the power supply current detecting means 6 includes the current transformer C. T. , The power supply current is detected, but this is conventionally provided for overcurrent detection, and does not add a new component. Instead of the power supply current detecting means 6, a current sensor or the like may be attached to the output side of the A / D converter 3.

The energization phase setting means 7 sets the energization phase at predetermined time intervals according to the information indicating the rotation condition, and sets the energization phase according to the current value detected by the power supply current detection means 6.
This is to increase or decrease the energization phase. To elaborate,
At a certain time, the energizing phase and the current value from the power supply current detecting means 6 set according to the rotation condition are compared with the energizing phase and the current value set in the processing performed one time before that time, respectively. Then, a new energization phase setting value is set by increasing or decreasing the energization phase setting value by a predetermined amount based on the comparison result.

The rotation condition information input to the energization phase setting means 7 includes information proportional to the motor speed, for example, motor speed information obtained from the above speed control circuit, or information proportional to the motor torque. For example, the output of a torque sensor or the like is used, but either one of the information or both of the information may be input.

The power distribution means 8 determines the power supply timing to the motor coil based on the rotation phase detected by the rotor phase detection means 5 and the power supply phase set value set by the power supply phase setting means 7. The energization signal is distributed to each drive element in the inverter circuit 4 according to the energization timing.

As described above, in the motor control device according to the present embodiment, the rotation phase of the motor is detected by the rotor phase detection means 5, input to the current distribution means 8, and the current is minimized by the current phase setting means 7. The energization phase is set or changed so that the following applies (details will be described later), and the energization timing is determined by the energization distribution means 8 by advancing or delaying the energization phase by the energization phase set value based on the rotational phase. At the same time, the energization signal is distributed to the U, V, and W phases, and the IPM motor 1
It is configured to rotate at the highest efficiency.

Next, the operation of the energization phase setting means 7 will be described in detail. As described above, when the IPM motor is used as the motor, there is an optimal energization timing according to the ratio of the reluctance torque and the framing torque. The efficiency is maximized at the optimal energization timing, that is, the energization phase, and the efficiency is deteriorated at other energization phases.

When the above efficiency is considered as a total efficiency including the IPM motor 1, the inverter circuit 4, and the A / D converter 3, this efficiency is represented by (output power) / (input power). The output power is obtained from the rotation speed and torque of the motor, and the input power is obtained from the input voltage and current to the converter circuit. Generally, the input voltage is
Since the input power is given as a rated power supply voltage, if the input voltage is almost constant, the input power can be obtained only by detecting the current.

Here, the characteristics of the power supply current with respect to the set value of the energization phase under a certain rotation condition are shown in the graph of FIG. In the graph of the characteristic 1 in FIG. 3, the conduction phase β0 having the minimum power supply current Imin is the optimum conduction phase, and the input power is minimum, that is, the efficiency is maximum by setting the conduction phase to β0. In FIG. 3, the energization phase set value of the X-axis advances as it goes to the right. The energization phase setting means 7 in the present embodiment includes:
The energization phase is automatically controlled to the energization phase β0 at which this minimum current is obtained.

A method for setting the energizing phase by the energizing phase setting means 7 to the energizing phase β0 at which the energizing phase becomes the minimum will be described with reference to FIG.

FIG. 4 is a flowchart showing the flow of processing in the energization phase setting means 7. First, step 5
In 1 (hereinafter referred to as S51), it is determined whether a predetermined time Twait has elapsed. The predetermined time Twait may be set as a fixed time, but it is more effective if set as described later.

After S51, it is determined in S52 whether or not the rotation condition has been changed. If there has been no change (NO in S52), the processing of S54 and later described later is performed. If there is a change (YES in S52), in S53, the energizing phase set value β is set to the energizing phase initial value βini that does not cause step-out corresponding to the rotation condition and extreme deterioration of efficiency. S to be described later
Step 60 is executed to end the series of processing. Then, after the elapse of the predetermined time Twait, the processing from S51 for searching for the minimum current again is repeatedly performed.

In S54, the current value detected by the power supply current detecting means 6 is read as Inow.

In S55, the current value Ila read last time is
The st is compared with the current value Inow read this time to determine the direction of the current change, that is, whether the current has increased or decreased compared to the previous time. Then, the comparison result is stored in Iresult as a current value comparison result.

In S56, the current setting value βlast at the time when the previous current value Ilast was read, and the current current value Ino
By comparing the energization phase setting value βnow at the time when w is read, the direction of the energization phase change, that is, whether the energization phase is advanced or delayed compared to the previous time is determined. The result of this comparison is βresult
Is stored in This βresult is known at the time of setting the energization phase setting value β described later without performing the comparison operation in S56, and may be stored at that time.

In S57, an exclusive OR is performed on Iresult and βresult, and the two comparison results are determined.

S58 is YES in S57, that is, both Iresult and βresult are the current values Inow and βnow.
Is larger (>,>), or Iresult, βresult
In both cases, the previous values Ilast and βlast are larger (<, <)
The processing is performed when the result is as follows. At this time,
As the energization phase set value β, a value obtained by reducing the energization phase change amount Δβ from the previously set energization phase set value βnow is set.

If NO in S57, that is, if the result is other than the above result, S59 is executed. At this time, the energization phase set value β is set to a value obtained by increasing the energization phase change amount Δβ from the previously set energization phase set value βnow.

In S60, the value of βnow is stored in βlast, the value of β is stored in βnow, and the value of Inow is stored in Ilast, and one process is terminated. The above processing is repeated every predetermined time Twait.

Here, it is assumed that the energization phase set value β is advanced in the + direction, S58 is to make the energization phase more delayed, and S59 is to make the energization phase more advanced. Therefore, when the +/− direction of the energization phase setting value β is reversed, the determination process in S57 may be changed.

It should be noted that the energization phase change amount Δβ of the energization phase may be set as a certain value, but the method described later is more effective.

Next, the above-described processing will be specifically described based on the graph of the characteristic 1 in FIG. First, the initial phase was βs1, or βini1
It becomes. Then, it is assumed that the conduction phase is advanced to βs2 by the conduction phase change amount Δβ from the initial phase. At this time, the magnitude relation of the conduction phases is βs1 <βs2, and the magnitude relation of the currents is Is1> Is2. At this time, since the magnitude relation between the comparison results Iresult and βresult is opposite, the energization phase is further advanced by the energization phase change amount Δβ by the processing in S59, and the energization phase is set to βs3. Thereafter, as shown in FIG. 4, by repeating the same processing as described above, the energization phase converges to β0.

When the process shown in FIG. 4 is repeated, after the energization phase converges to β0, the energization phase fluctuates between βs4 and βs5 around β0 in the graph of characteristic 1 in FIG. become. However, the energizing phase change amount Δβ
Is set to an appropriate value, it is possible to make the efficiency reduction, speed fluctuation, and the like due to this fluctuation negligible. Further, it is detected that the energization phase has changed between βs4 and βs5, and when the phase becomes β0,
May be configured to stop the processing shown in FIG.

When the rotation conditions such as the number of rotations and the torque are changed, the characteristics are centered on βa0 as shown in the graph of characteristic 2 in FIG. Assuming that the rotation condition is changed from the characteristic 1 to the characteristic 2, first, the energized phase setting initial value βini2 is set to the energized phase set value β, and then control processing for minimizing the current to βa0 is performed. As a method for setting the energization phase change amount Δβ, a method described later is effective.

With such processing, the IPM motor 1 can always obtain the highest efficiency. That is, for example, even if an extreme decrease in torque occurs, the above S
By performing the processes in 52 and S53, the energization phase is newly set. That is, the energization phase setting value β is set to an energization phase that is suitable to some extent under the rotation conditions. Therefore, even when the rotation condition is changed, it is possible to prevent a decrease in the efficiency of the IPM motor 1 or a loss of synchronism, and to enhance the reliability of the high-efficiency operation.

A method different from the processing shown in FIG. 4 will be described below as the processing in the energization phase setting means 7 with reference to the flowchart shown in FIG.

First, in S71, it is determined whether or not a predetermined time Twait has elapsed, and then, in S72, it is determined whether the rotation condition has been changed. If there has been no change (NO in S72), S
The processing after 74 is performed. If there is a change (S72
YES in step S73), and limiter values βlower, β in the limit range of the lagging phase and the leading phase of the energizing phase in S73
Upper is provided, and the delay energization phase limiter value βlim1 and the advance energization phase limiter value βlim2 are set to βlo so that step-out and extreme deterioration of efficiency do not occur according to the rotation condition.
wer, stored in βupper.

At S74, the current value detected by the power supply current detecting means 6 is read as Inow.

At S75, the current value Ila read last time is
The st is compared with the current value Inow read this time to determine the direction of the current change, that is, whether the current has increased or decreased compared to the previous time. Then, the comparison result is stored in Iresult.

In S76, the current setting value βlast at the time when the previous current value Ilast was read and the current current value Ino
By comparing the energization phase setting value βnow at the time when w is read, the direction of the energization phase change, that is, whether the energization phase is advanced or delayed compared to the previous time is determined. Then, the comparison result is stored in βresult. This βresult can be known at the time of setting the energization phase setting value β described later without performing the comparison operation in S76, and may be stored at that time.

In S77, an exclusive OR is performed on Iresult and βresult, and the two comparison results are determined.

S78 is YES in S57, that is, both Iresult and βresult are the current values Inow and βnow.
Is larger (>,>), or Iresult, βresult
In both cases, the previous values Ilast and βlast are larger (<, <)
The processing is performed when the result is as follows. At this time,
As the energization phase set value β, a value obtained by reducing the energization phase change amount Δβ from the previously set energization phase set value βnow is set.

If NO in S77, that is, if the result is other than the above result, S79 is executed. At this time, the energization phase set value β is set to a value obtained by increasing the energization phase change amount Δβ from the previously set energization phase set value βnow.

Then, in S80, it is determined whether or not the energization phase setting value β is within the range from the limiter value βlower to βupper. If YES in S80, that is, if it is determined that the energization phase setting value β is within the range from the limiter value βlower to βupper, the process directly proceeds to S82. If NO in S80, that is, if it is determined that the energization phase set value β is not within the range from the limiter value βlower to βupper, a process of correcting the energization phase set value β to be within the limiter range is performed in S81. Will be This is because, for example, if the energization phase setting value β is a phase delayed from the limiter value βlower, the energization phase setting value β is corrected to the delay limiter value βlower, and the energization phase setting value β is advanced from the limiter value βupper. If there is, a process for correcting the energization phase setting value β to the limiter value βupper is performed.

In S82, the value of βnow is stored in βlast, the value of β is stored in βnow, and the value of Inow is stored in Ilast, and one process is terminated. The above processing is repeated every predetermined time Twait.

Accordingly, even when the rotation condition is greatly changed due to an extreme decrease in torque or the like, in the process of searching for the optimum energization phase, the energization phase is set to an energization phase that causes motor out-of-synchronization or extreme deterioration in efficiency. It is possible to prevent a value from being set. Therefore, the reliability of high efficiency operation can be improved.

Further, as another processing in the energization phase setting means 7, there is a processing as shown in a flowchart of FIG. The processing shown in FIG. 6 is a combination of the processing shown in FIG. 4 and the processing shown in FIG. 5 described above, and has both the effect of providing an initial value and the effect of providing a limiter. It is a process that can obtain both. The outline of this process is shown below.

First, in S91, it is determined whether a predetermined time Twait has elapsed, and then, in S92, it is determined whether the rotation condition has been changed. If there has been no change (NO in S92), S
The processing after 95 is performed. If there is a change (S92
At S93), and at S93, the energization phase set value β
Is set to the initial value βini of the energization phase in which the step-out corresponding to the rotation condition and the extreme deterioration of the efficiency do not occur. Then, in S94, limiter values βlower and βupper are set to limit the lagging phase and the leading phase of the energizing phase, and the lagging energizing phase is set to a range where step-out and extreme deterioration of the efficiency do not occur according to the rotation condition. The limiter value βlim1 and the leading energization phase limiter value βlim2 are set to βlower and βup, respectively.
Store in per. Thereafter, S103 to be described later is executed, and the series of processing ends. Then, a predetermined time Twa thereafter
After the passage of it, the processing from S91 for searching for the minimum current again is repeatedly performed.

In the subsequent steps S95 to S103, the same processing as the processing in steps S74 to S82 of the processing shown in FIG. 5 is performed.

As described above, depending on the energization phase, there is a range of the energization phase in which the total torque T extremely decreases as shown in FIG. If the IPM motor 1 is operated within such a range of the energizing phase, in the worst case,
The M motor 1 may lose synchronism. Since such an energization phase differs depending on the rotation condition, when the rotation condition changes, the optimum energization phase also changes. Therefore, when the rotation condition changes, step-out,
It is conceivable that a problem such as a reduction in efficiency or an increase in the time required for convergence to the optimal energization phase in which the current is minimized occurs.

In this regard, in the processing shown in FIG. 4, the processing of S52 and S53 is performed, and in the processing shown in FIG.
In the processing of 72, S73, S80, and S81, and in the processing shown in FIG. 6, S92, S93, S94, S101, and S1
By the process of 02, it becomes possible to cope with the change of the optimum energization phase due to the change of the rotation condition. Therefore, even in a usage environment where the rotation conditions change every moment, it is possible to prevent loss of synchronism and efficiency, and to control the energization phase to achieve the highest efficiency reliably and with high reliability. It can be carried out.

In the above processing, the initial value βini
, And the limiter values βlim1 and βlim2 are, for example, under rotation conditions as shown in the graph of the characteristic 1 in FIG.
As shown in (1), each value may be set within a range that enables the above-described optimal energization phase search.
Such values are stored in ROM (Read Only Memory) for each rotation condition.
The energization phase information may be stored in advance in y) or the like, and may be called up, or may be obtained by calculation or the like.

Although the rotation condition is strictly changed, it always changes slightly. However, if the change is slight, it is not necessary to change the initial value βini and the limiters βlim1 and βlim2. This is the initial value βini and the limiter value β
This is because, if lim1 and βlim2 are frequently changed, the processing time may be increased or the processing for searching for the optimal energization phase may be hindered. Therefore, it is necessary to determine how much the experimental conditions change the initial value βini and the limiter values βlim1 and βlim2 in an experiment or the like, and use this as a criterion in S52, S72, and S92. desirable.

When the rotation condition changes, the energization phase may be changed in the direction opposite to the direction in which the power supply current is minimized. However, this is only one time when the rotation condition is changed. There is little substantial problem, and when the rotation condition is changed, the previous energization phase, current value, and the like may be discarded, and the energization phase may be arbitrarily changed to start a new energization phase control process.

It should be noted that the present invention performs the automatic optimal phase control, and also sets the initial value βini,
Alternatively, the limiters βlim1 and βlim2 are set, and if these requirements are satisfied, the present invention is not limited to the processing in the flowcharts of FIGS.

Next, the setting of the energization phase change amount Δβ of the energization phase detection means 7 will be described below with reference to FIG. FIG. 7 is a graph showing a relationship between an energizing phase under a certain rotation condition and a power supply current at that time.

In the processing described with reference to FIG. 3, the processing is performed with the energization phase change amount Δβ being constant, but in this example, the energization phase change amount Δβ is determined based on the current change amount with respect to the energization phase change amount. To set.

As described above, in the IPM motor 1, the optimum energizing phase changes every moment depending on the rotation condition. In order to operate at the highest efficiency, it is necessary to determine the energization phase in accordance with changes in the rotation conditions, and a high-speed response is required. By the processing shown in this example, it is possible to secure high-speed control and to achieve high accuracy.

As shown in FIG. 7, in the processing according to the present embodiment, the energizing phase change amount Δβ is set to be large when the ratio of the current change amount to the energizing phase is large, and conversely, when the ratio is small, the energizing phase change amount Δβ is set to It is set to be small. The energization phase change amount Δβ may be obtained by calculating the differential value of the current change with respect to the energization phase, may be set to a predetermined change amount according to the change rate, or regardless of the energization phase. The setting may be made based only on the amount of change in the current. Further, for example, when the change in current is equal to or less than a predetermined amount, a process such as changing the energization phase change amount Δβ stepwise may be added, such as not changing the energization phase.

Thus, the time required for the search for the optimal energization phase to converge can be shortened, and the fluctuation of the energization phase after the convergence can be suppressed to a small value. Therefore,
High-speed and accurate control of the energization phase can be performed.

Next, the setting of the predetermined time Twait serving as the current reading timing in the energization phase detecting means 7 will be described below.

The IPM motor 1 receives various load torques as described below, and these rarely have no fluctuation at all, and often have periodic fluctuations. Normally, when there is a torque fluctuation, the current fluctuates similarly in order to keep the rotational speed fluctuating accordingly.

FIG. 8 is a graph showing the fluctuation characteristics when the rotation phase θ of the IPM motor 1 is set on the X axis and the load torque by the motor bearing or the like is set on the Y axis. FIG.
As shown in (1), each time the IPM motor 1 makes one rotation, one torque fluctuation often occurs.

FIG. 9 is a graph showing the characteristics of the motor torque ripple generated in the cycle of the least common multiple of the number of motor poles and the number of motor coils in the IPM motor 1. As shown in FIG. 9, in the case of a 4-pole, 6-coil motor, IPM
Each time the motor 1 makes one rotation, twelve torque fluctuations occur.

FIG. 10 is a graph showing torque fluctuations due to the compression cycle of the scroll type compressor and the rolling piston type compressor. As shown in FIG. 10, even in a scroll-type compressor which is considered to have relatively small torque fluctuation, torque fluctuation periodically exists.

FIG. 11 is a graph showing an example of torque fluctuation of a device in which a motor is incorporated. As shown in FIG. 11, it can be seen that torque fluctuations occur in various cycles depending on the device.

Here, as described above, the energizing phase setting means 7 in the present embodiment compares the current value read last time with the current value read this time, as shown in FIGS. 8 to 11. In the case where there is a large torque fluctuation, a malfunction occurs unless the currents at the same torque fluctuation position are compared.

Therefore, a predetermined time Twait which is a current reading timing synchronized with each torque fluctuation is set, and the processing is performed using the predetermined time Twait as a control cycle.

The detection of each fluctuation cycle can be performed as follows. First, the torque fluctuation synchronized with the rotation as shown in FIG. 8 and the torque ribble as shown in FIG. 9 can be detected by the rotor phase detecting means 5. The torque fluctuation as shown in FIG. 10 may use a pressure sensor or the like, and the torque fluctuation as shown in FIG. 11 may use a torque sensor or the like.

Further, since the current comparison may be performed at the same position of the torque cycle, the current may be read a plurality of times during one cycle, for example, and the comparison may be performed at the same position.

If the predetermined time Twait is set as described above, the read current timing always becomes the same fluctuating position as shown by Ts in, for example, FIGS. 8 to 11, so that accurate comparison can be realized and high accuracy can be achieved. Control becomes possible.

Further, regarding the setting of the predetermined time Twait,
It is preferable to consider the following. FIG.
2 is a graph showing a time change of the motor rotation speed of the IPM motor 1 when the energization phase is changed.

Normally, the control of the motor rotational speed by the speed control circuit has a control delay time. That is,
If any element of the rotation condition changes, the motor rotation speed changes, but it takes some time until the rotation speed converges to a predetermined value. For example, when the IPM motor 1 is operated while the energization phase is changed, the motor rotation speed changes due to the influence of the above-mentioned weak magnetic flux, the influence of the increase and decrease of the generated torque, and the like. Then, a control convergence time Tcnt is required as shown in FIG. 12 until the fluctuation is suppressed by the control by the speed control circuit.

Within the control convergence time Tcnt, the motor rotational speed fluctuates, which is the same as the change in the rotational condition. Therefore, even if the current value is compared with the previous current value within the control convergence time Tcnt, it is not possible to expect highly accurate control. Note that such fluctuations in the motor rotation speed due to disturbance are particularly noticeable when the control characteristics of the speed control circuit are low.

Therefore, when the predetermined time Twait for determining the current reading timing is set, the control convergence time Twait is set.
It is preferable to consider cnt.

Although the control convergence time Tcnt varies depending on the energization phase change amount Δβ and the like, the control convergence time Tcnt may be determined as a certain value, and may be considered when setting the predetermined time Twait. The predetermined time Twait may be set according to the energization phase change amount Δβ. Alternatively, if the fluctuation amount (convergence degree) of the motor rotation speed is actually detected from the motor rotation speed information, the predetermined time Twait can be set more accurately.

The control convergence time Tcnt may be detected based on whether or not the fluctuation of the motor rotation speed is within a predetermined range. In addition, for example, when the fluctuation of the load torque is large in consideration of the torque fluctuation and the like, the time to settle down, that is, the control convergence time Tcnt is detected as described above, and the predetermined time Twait is set according to the result. May be.

By setting the predetermined time Twait as described above, comparison can always be performed under the same rotation condition, and control with high accuracy can be realized.

In the above series of explanations, it is assumed that appropriate values are stored as the initial values of the variables used in each process. Further, if the configuration for performing the above-described processing is configured by software using a microcomputer or the like, the circuit scale does not increase.

[0116]

As described above, the motor control apparatus according to the first aspect of the present invention provides a reluctance torque generated by the change in the armature winding inductance and the armature current,
In a motor control device for driving a motor that uses a magnetic flux of a permanent magnet and a framing torque generated in association with an armature current, a rotor phase detecting means for detecting a rotation phase of a rotor in the motor, a driving power source Power supply current detection means for detecting the current value of the power supply current at
A motor coil in the motor based on the energization phase setting means for setting the energization phase set value every predetermined time; the rotation phase detected by the rotor phase detection means; and the energization phase set value set by the energization phase setting means. Power supply distribution means for determining a power supply timing to each drive element in the motor, and a power supply distribution means for distributing a power supply signal to each drive element.The power supply phase setting means includes a current value read last time and a power supply phase set value at that time, A configuration in which the current value read this time and the energizing phase setting at that time are respectively compared, and based on the comparison result, the energizing phase setting is increased or decreased by a predetermined energizing phase change amount, and a new energizing phase setting is set. It is.

As a result, even when the rotation conditions fluctuate, it is possible to successively search for and set the optimum energization phase. Therefore, the motor can always be driven with the optimal energization phase that minimizes the power supply current,
There is an effect that the motor can be operated with extremely high efficiency.

The motor control device according to the second aspect of the present invention
When the energization phase setting means changes the rotation condition,
This is a configuration in which the energization phase setting value is set to an energization phase setting initial value set according to the rotation condition.

Thus, in addition to the effect of the configuration of the first aspect, even when the rotation condition is largely changed, the conduction phase set value is set to a conduction phase suitable to some extent under the rotation condition. Therefore, even if the rotation condition is largely changed, it is possible to prevent the motor from stepping out or extremely lowering the efficiency, and it is possible to improve the reliability of the motor with high efficiency operation.

A motor control device according to a third aspect of the present invention
The energizing phase setting means sets the energizing phase set value within a range of a limiter value set according to the rotation condition.

Thus, in addition to the effect of the configuration of the first aspect, even when the rotation condition is greatly changed, for example, in the process of searching for the optimum energizing phase, the motor may lose synchronism or the efficiency may be extremely deteriorated. It is possible to prevent the energization phase setting value from being set in the energization phase. Therefore, there is an effect that the reliability of high-efficiency operation of the motor can be improved.

A motor control device according to a fourth aspect of the present invention
The power supply phase setting means determines the power supply phase change amount based on a ratio of a power supply current change amount to a power supply phase change amount.

Thus, in addition to the effect of any one of the first to third aspects, it is possible to set the energization phase set value to an optimum energization phase that fluctuates depending on the rotation conditions at a high speed. Phase fluctuations after the set value converges to the optimal energizing phase can also be suppressed to a small value. Therefore, high-speed and high-accuracy energization phase control can be performed, so that the motor can be operated with higher efficiency.

A motor control device according to a fifth aspect of the present invention
In this configuration, the predetermined time is set so as to synchronize with the torque fluctuation of the motor.

As a result, in addition to the effect of any one of the first to third aspects, the current value can be compared more accurately. Therefore, the search for the optimum energization phase can be performed more accurately, so that the operation of the motor can be performed with higher efficiency.

A motor control device according to a sixth aspect of the present invention
When the rotation speed of the motor fluctuates when the energization phase is changed, the predetermined time is set to be equal to or longer than the control convergence time until the fluctuation in the rotation speed of the motor stops.

Thus, in addition to the effect of any one of the first to third aspects, it is possible to prevent the fluctuation of the rotation speed of the motor from adversely affecting the search for the optimum energization phase. Therefore, the search for the optimum energization phase can be performed more accurately, so that the operation of the motor can be performed with higher efficiency.

The motor control device according to the invention of claim 7 is:
The energization phase setting means stores, at predetermined time intervals, a comparison result of the current value read this time and the current value read last time as a current value comparison result. Is stored as an energized phase comparison result, and an exclusive OR operation is performed on the current value comparison result and the energized phase comparison result to determine the sign of addition or subtraction of the energized phase change amount, and a new energization is performed. This is a configuration for setting a phase setting value.

Thus, in addition to the effect of the configuration of the first aspect, it is possible to search for the optimum energization phase without performing complicated processing. That is, there is an effect that the highest efficiency operation of the motor can be realized simply and efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a motor control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an internal configuration of a rotor in an IPM motor provided in the motor control device.

FIG. 3 is a graph showing characteristics of a power supply current with respect to an energization phase set value under a certain rotation condition in the IPM motor.

FIG. 4 is a flowchart showing a flow of processing in an energization phase setting means provided in the motor control device.

FIG. 5 is a flowchart showing a flow of another processing in the energization phase setting means.

FIG. 6 is a flowchart showing a flow of still another process in the energization phase setting means.

FIG. 7 is a graph showing the characteristics of the power supply current and the amount of change in the energization phase with respect to the energization phase set value under a certain rotation condition in the IPM motor.

FIG. 8 is a graph showing fluctuation characteristics when the rotation phase θ of the IPM motor is set on the X axis and the load torque by the motor bearing or the like is set on the Y axis.

FIG. 9 is a graph showing characteristics of motor torque ripple generated in a cycle of the least common multiple of the number of motor poles and the number of motor coils in an IPM motor.

FIG. 10 is a graph showing torque fluctuations due to a compression cycle of a scroll compressor and a rolling piston compressor.

FIG. 11 is a graph showing an example of torque fluctuation of a device in which a motor is incorporated.

FIG. 12 is a graph showing a time change of the motor rotation speed of the IPM motor when the energization phase is changed.

FIG. 13 is a graph showing an example of a relationship between a timing at which a current flows through a coil winding of an armature, that is, a conduction phase, various torque values, and a terminal voltage in an IPM motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IPM motor 2 AC power supply 3 A / D converter 4 Inverter circuit 5 Rotor phase detection means 6 Power supply current detection means 7 Current supply phase setting means 8 Current supply distribution means 9 Permanent magnet 10 Iron core

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) EE18 FF03 GG01 GG06 HB01 JJ03 KK06 LL16 LL22 LL25 LL39 LL41 MM20

Claims (7)

[Claims] 1. A motor that utilizes a reluctance torque generated by an inductance change of an armature winding and an armature current and a flaming torque generated by a magnetic flux of a permanent magnet and an armature current in combination. A motor control device for driving; a rotor phase detecting means for detecting a rotation phase of a rotor in the motor; a power supply current detecting means for detecting a current value of a power supply current in a driving power supply; An energizing phase setting unit, a rotation phase detected by the rotor phase detecting unit, and an energizing phase setting value set by the energizing phase setting unit, and determining an energizing timing of a motor coil in the motor, And an energization distributing means for distributing an energization signal to each drive element in the above. The current value input and the current conduction phase set value at this time are respectively compared with the current value read at this time and the current conduction phase set value, and based on the comparison result, the current conduction phase set value is changed by a predetermined conduction phase change amount. A motor control device characterized in that a new energization phase setting value is set by increasing or decreasing the current value. 2. The power supply phase setting means sets a power supply phase setting value to a power supply phase setting initial value set according to the rotation condition when the rotation condition is changed. 2. The motor control device according to 1. 3. The motor control device according to claim 1, wherein said energization phase setting means sets the energization phase set value within a range of a limiter value set according to a rotation condition. 4. The power supply phase setting means according to claim 1, wherein said power supply phase setting means determines the power supply phase change amount based on a ratio of a power supply current change amount to a power supply phase change amount. 3. The motor control device according to claim 1. 5. The apparatus according to claim 1, wherein the predetermined time is set so as to synchronize with a torque fluctuation of the motor.
4. The motor control device according to any one of claims 3 to 3. 6. When the rotation speed of the motor fluctuates when the energization phase is changed, the predetermined time is set to be equal to or longer than the control convergence time until the fluctuation of the rotation speed of the motor stops. 4. The method according to claim 1, wherein:
The motor control device according to any one of the above. 7. The power supply phase setting means according to claim 1, wherein:
The comparison result between the current value read this time and the current value read last time is stored as the current value comparison result, and the comparison result between the current conduction phase setting value and the previous conduction phase setting value is stored as the conduction phase comparison result. Performing an exclusive OR operation on the current value comparison result and the conduction phase comparison result to determine an addition / subtraction sign of the conduction phase change amount and set a new conduction phase setting value. Item 2. The motor control device according to Item 1.